Mint plant named ‘Clackamas’

ABSTRACT

A new and distinct peppermint plant ‘Clackamas’ characterized by its resistance to Mint rust ( Puccinia menthe  Pers), Mint wilt ( Ferticillium dahliae  and  Verticillium albo - atrum ), and Spider mites as well as a more upright growth habit and a lighter green color the Black Mitcham peppermint plant.

Latin name of the genus and species of the plant claimed:Mentha×piperita.

Variety denomination: ‘Clackamas’.

FIELD OF THE INVENTION

The present invention relates to a new and distinct peppermint plantbotanically known as Mentha×piperita. The new variety has been named‘Clackamas’ and will be referred as such hereafter.

BACKGROUND OF THE INVENTION

The new peppermint plant of the present invention was developed in aneffort to cultivate a peppermint variety exhibiting an upright growthhabit, vigorous and abundant root growth, greater resistance to Mintrust (Puccinia menthe Pers), Verticillium wilt (Verticillium dahliae andV. albo-atrum), and Spider mites (Tetranychus urticae). Further,‘Clackamas’ produces a peppermint oil that varies minimally in oilprofile based on plant maturity.

The inventor explored ways of creating peppermint hybrids throughconventional crosses from the ‘Black Mitcham’ (Mentha piperita)—notpatented—parent plants without the use of chemicals to increase ploidy.The method relied on adjusting environmental conditions to generateviable pollen. Using this method, several seedlings were generated in1996 using two ‘Black Mitcham’ peppermint plants as parents.

The resulting selection has been under continuous evaluation at the A.M. Todd facility located in Jefferson, Oreg. since 1996 and has beenasexually propagated through propagules and rhizome cuttings. Theresulting propagules have remained identical to the parent plantregarding resistance to the common diseases encountered by mint plantsin general and exhibiting heartier and more upright growth habit ascompared to ‘Black Mitcham.’

SUMMARY OF THE INVENTION

The present invention relates to a novel mint plant named ‘Clackamas’characterized by its more upright growth habit as shown by taller growthwith thicker stems, when compared to commercial peppermint varieties,more abundant and vigorous root growth and resistance to Mint rust(Puccinia menthe Pers), Verticillium wilt (Verticillium dahliae and V.albo-atrum), and Spider mites (Tetranychus urticae), and more uprightgrowth habit as shown by taller growth with thicker stems, larger leavesand a lighter green color, when compared to ‘Black Mitcham.’ Thepeppermint oil profile of ‘Clackamas’ is also similar throughout itsmaturity when grown in Oregon and Washington.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying color photographs of ‘Clackamas’ show the new variety:

FIG. 1: shows cuttings of the claimed plant ‘Clackamas’ including itsfoliage and inflorescences.

FIG. 2: shows the flower spike of ‘Clackamas.’

FIG. 3: shows the mature leaves of ‘Clackamas.’

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a new and distinct variety of a Mentha×piperitapeppermint plant having the following characteristics that, incombination, are not exhibited in other peppermint plants:

1. More upright growth habit;

2. More vigorous and abundant root growth;

3. Oil profile that shows little variability based on plant maturity;

4. Improved resistance to Mint rust (Puccinia menthe Pers);

5. Improved resistance to Verticillium wilt (Verticillium dahliae and V.albo-atrum);

6. Improved resistance to Spider mites (Tetranychus urticae); and

7. A lighter green color.

‘Clackamas’ is an herbaceous perennial with an upright shrubby growthhabit. The observed plants were two years old and were grown outdoors inwestern Oregon, in a silt-loam soil. Based on initial May plantingdensity of 8,000 plants per acre, a new ‘Clackamas’ rootstock fieldwould fill in by mid-June. The density of rhizomes from this acre ofrootstock allows for a 10 to 1 expansion the following season, which issimilar to ‘Black Mitcham.’ Numerous branching stems are produced eachyear with an eventual height between 60-80 cm. The approximate plantspread is in the range of 12-22 cm reflecting a size measurement halfway up the plant during bloom on a managed field plot. Measurementstaken at different times of the year, on different locations of theplants, under different crop management regimes will vary. As‘Clackamas’ is a rhizomatous perennial, it is not possible to specifythe accurate dimensions of one single plant because the differentiationof where one plant terminates and another begins is unknown. At the endof one growing season, it is estimated that one rooted cutting will havespread through a four square foot area. When compared to ‘BlackMitcham,’ the industry standard, which is not patented and has beencommercially grown for hundreds of years, ‘Clackamas’ is more upright inits growth habit, taller with thicker stems (due to a large extent tothe highly lignified stems which reduces lodging), larger leaves and alighter green color with less anthocyanin pigment development undersimilar growing conditions.

‘Clackamas’ has a square stem, in the range of 5 mm on a side, compareto the average 4.5 mm stem of ‘Black Mitcham.’ Stems and leaves,especially along leaf veins, are sparsely pubescent and more so than‘Black Mitcham.’ Based on flowering ‘Clackamas’ matures at approximatelythe same time as ‘Black Mitcham.’ ‘Clackamas’ also features theadditional benefit of vigorous and abundant root growth, which resultsin more rapid acreage expansion and reduction in planting costs. Ascompared to the peppemint plant ‘McKenzie,’ which is disclosed inco-pending application No. 10/193,191, ‘Clackamas’ has a shorter flowerspike, thinner stems, lighter leaf color, and on average a shortergrowth habit with smaller leaves.

All color descriptions according to The R.H.S. Colour Chart. Inbotanical terms, ‘Clackamas’ has ovate leaves with a serrate margin. Theleaves are oppositely arranged on the stem with an equilateral base, anacute apex, and serrate margin. Ventral leaf surface color is 147A(Yellow-Green Group), dorsal color is 147B (Yellow-Green Group), petiolecolor is 147C (Yellow-Green Group). Stem color is 146C (Yellow-GreenGroup) near the base and gradually becomes more purple until the colorat the apex is 187A (Greyed-Purple Group). The fragrance ispeppermint-like.

In contrast to the red pigments found in ‘Black Mitcham,’ the leaves of‘Clackamas’ are slightly narrower and also light green in color. Theflower spike of ‘Clackamas’ is more elongated than ‘Black Mitcham’ undersimilar growing conditions and the number of paired flower whorls, orverticillasters varies from 8-15. The first internode between verticelsvaries from 1 to 3 cm. The individual flowers of Clackamas contain a4-lobed, nearly regular corolla 73D (Red-Purple Group) with a shorttube, 7 mm long from the base of the calyx to the tip of the forkedwhite stigma. The calyx has an average of five ciliate teeth fused atthe base forming a short tube and is 4 mm long. The calyx, peduncle andpedicel colors are 187A (Greyed-Purple Group). Each flower has onepistil with a 6 mm long white style and four epipetalous stamens thatmay be exerted with 3 mm long white filaments. The white anthers areless than 1 mm. Pollen color is 10D (Yellow Group). The formation ofseed is a rare event. There is no obvious flower fragrance. The flowercolor is also whiter in color as compared to the mostly lavender ‘BlackMitcham.’

The oil produced by ‘Clackamas’ is of a typical peppermint type. Incontrast to ‘Black Mitcham’ the peppermint oil profile of ‘Clackamas’varies little with plant maturity. This feature allows for increasedyield due to flexible harvest timing during a single season withoutsignificant changes occurring to its peppermint oil profile. ‘Clackamas’has an herbage yieldage of approximately 80 lbs./acre and an essentialoil quality of peppermint oil having 5 to 10 percent higher level ofmenthyl acetate than standard ‘Black Mitcham’ peppermint.

‘Clackamas’ has been grown and observed under 3 different fieldconditions as well as under greenhouse conditions. As with all plants,the traits have varied depending on location. These differences can beattributed to varying climates, soils, fertilizers and water regimes.However, ‘Clackamas’ remains distinct from other peppermint plants inits characteristics. The resistance to the diseases identified above ispresented in Table I. The results were gathered from a study performedin western Oregon and show the comparison of ‘Clackamas’ to ‘BlackMitcham’ according to the mean number of rust pustules per leaf, meannumber of Verticillium strikes per plot and mean number of spider mitesper leaf during three years of analysis.

TABLE I Mean Number of Mean Number Mean Number of Verticillium of SpiderRust Pustules strikes Mites per Variety per leaf per plot leaf Aug. 15,1999 ‘CLACKAMAS’ 5.00 0.25 1.00 ‘Black Mitcham’ 40.30 9.25 8.25 Aug. 22,2000 ‘CLACKAMAS’ 20.25 1.25 0.38 ‘Black Mitcham’ 183.25 17.00 10.00 Aug.26, 2001 ‘CLACKAMAS’ 5.75 2.75 0.00 ‘Black Mitcham’ 81.25 30.50 11.25

As illustrated by Table I, ‘Clackamas’ is significantly more resistantto the diseases shown. For example, although the incidence of Mint Rustvaried overall according to the three years shown due to differences inannual growing conditions, ‘Clackamas’ consistently showed greaterresistance to Puccinia menthe Pers when compared to the mean number ofRust Pustules per leaf. Similarly, the number of mean strikes per plotfor Verticillium dahliae and Verticillium albo-atrum was markedlyreduced by ‘Clackamas’ when compared to ‘Black Mitcham’. In the case ofTetranychus urticae, the man number of Spider Mites per leaf was almosteliminated in comparison to ‘Black Mitcham’.

While the plant identified in the present invention has been describedas it relates to a specific embodiment, it is understood that thisapplication is intended to cover other variations, uses and adaptationsthat may arise under different environmental conditions.

What is claimed is:
 1. A new and distinct variety of Mentha×piperitaplant named ‘Clackamas’ substantially as shown and described herein.